fix #330: clearFrames does nothing
fix #330: clearFrames does nothing

mkeilman/sirepo,radiasoft/sirepo,radiasoft/sirepo,mkeilman/sirepo,radiasoft/sirepo,mkeilman/sirepo,mrakitin/sirepo,radiasoft/sirepo,mrakitin/sirepo,radiasoft/sirepo,mrakitin/sirepo,mrakitin/sirepo,mkeilman/sirepo